Vaccination against Covid-19 continues to advance in Spain, when there are already four different types of authorized vaccines that are administered in our territory, which differ in different aspects, such as the efficacy, the age range in which they are distributed, the side effects or the number of doses.
Thus, although it seems that the vaccination rate is going faster and faster, doubts continue to arise among the population around AstraZeneca, Janssen, Pfizer or Moderna, the four available right now in the country.
Differences in Vaccine Efficacy
First, Vaxzevria vaccine, from Oxford and AstraZeneca, has a proven efficacy of 76% after a first dose, with protection maintained until the second dose. With an interval between doses of 12 weeks or more, the efficacy of the vaccine increases up to 82%, according to the results of the study published by AstraZeneca.
In second place, the Comirnaty vaccine, from Pfizer-BioNTech, demonstrated in previous studies 94.6% efficiency in participants with or without evidence of previous infection. Efficacy in participants without evidence of prior infection was 95% and in the 65-year-old or older group, efficacy was 94.7%. In the age group of 75 years or more, it was 100%, but with a non-significant confidence interval, according to the technical guide of the Ministry of Health.
On the other hand, Moderna’s vaccine, according to the data provided by the manufacturer, it shows to have an effectiveness of 94.1% in a large-scale clinical trial already conducted. Efficacy in participants at high risk of serious infection was 94.4%, according to data provided by Health.
By last, Janssen’s vaccineAccording to data provided by the manufacturer and collected by the World Health Organization, the Johnson & Johnson vaccine has been shown to be 66.9% effective in an ongoing large-scale clinical trial.
Differences in technology and required doses
To achieve the desired efficacy, both the Pfizer, AstraZeneca and Moderna vaccines require two doses. The only one that is single-dose, that is, it only requires one dose to complete the vaccination, It’s Janssen’s.
However, some manufacturers were already considering the possibility of injecting the population with a third booster dose, as is the case with Pfizer, which is proposing a combination of a third dose of the vaccine with 20vPnC.
As for the technology used in each vaccine, there are also differences. On the one hand, Pfizer and Moderna vaccines use a new messenger RNA technology, while the Janssen and Astrazeneca vaccines use the well-known inactivated adenovirus method.
Differences in side effects
Like other medications, treatments, and vaccines, the different types of Covid-19 injections can cause side effects in people, these being the most common in each of them, together with the percentage reflected in the studies collected by each of the technical Health guides.
The Comirnaty vaccine, that is, Pfizer’s, has the following most common adverse reactions:
Injection site pain (> 80%) Fatigue or tired feeling (> 60%) Headache (> 50%) Myalgia and chills (> 30%) Arthralgia (> 20%) Injection site fever and swelling ( > 10%)
The AstraZeneca and Oxford Vaccine can cause the following most common side effects:
Injection site swelling (> 60%) Injection site pain, headache and tiredness (> 50%) Myalgia and malaise (> 40%) Fever and chills (> 30%) Arthralgia and nausea (> 20%) ) Fever ≥38ºC (> 7%).
Janssen’s vaccineAccording to studies, it produces these side effects:
Injection site pain (> 40%) Headache, fatigue and myalgia (> 30%) Nausea (Fever (9%)
Moderna’s vaccine can produce these adverse reactions, the most common being:
Injection site pain (> 90%) Fatigue or tired feeling (70%) Headache (> 60%) Myalgia (> 60%) Arthralgia and chills (> 40%) Nausea or vomiting (> 20%) Axillary lymphadenopathy , fever, swelling and redness at the injection site (> 10%)
In addition to these more common side effects, others may occur less frequently. It is the case of people who have developed thrombosis after injection by AstraZeneca vaccine. The Ministry of Health confirmed at the end of May that four people have died in Spain after receiving the Oxford vaccine due to thrombosis with low platelet levels, in addition to counting, at that time, another 16 confirmed or suspected cases.
Age groups for each vaccine
In the case of the vaccine AstraZeneca, health authorities recommend do not inject it to children under 60 years due to the risk of thrombi. In fact, people younger than that age have been encouraged to complete their immunization with a second injection of Pfizer if they had the first dose of AstraZeneca.
In this way, following the vaccination plan by age groups that has been taking place since the beginning of the campaign, everyone under the age of 60 can receive any of the vaccines, based on availability, except for AstraZeneca.
